I used to just tough it out to the end of the week. But I don't know if you wanna do that...

Best thing to do (IMO) is get to bed early the next day (tonight) and then sleep as long as your body wants to. That generally puts you back on the right schedule. If you go to sleep at like 9 or 10 PM and then wake up anywhere from 6-8 depending on how the body is feeling.

This would, of course, leave you to study for your math test sometime during today and then write the rest of your papers tomorrow... but it's doable.